The broad objectives in our study of oxygen-carrying hemeproteins are an understanding of (a) the mechanisms by which the properties of a prosthetic group are modified by a protein environment and of (b) the nature of the involvement of the heme group in the protein conformational changes which constitute the cooperative mechanism of hemoglobin function. We propose to pursue these objectives through studies of the hemoglobin residual oxidation Bohr effect, of the photosensitivity of hemoglobin and metal-substituted hemoglobins, and of other properties of these latter hemoglobin analogues. BIBLIOGRAPHIC REFERENCES: "Linearity of the Hemoglobin Oxidation Bohr Effect," Proc. Nat. Acad. Sci., 73, 800 (1976), Brian M. Hoffman and Chris Bull. "Anomalous Azide Binding to Met-Manganomyoglobin," Biochem. 15, 3405 (1976), Brian M. Hoffman and Quentin H. Gibson.